Funds are requested for the purchase of a computerized chromosome analysis system which will be applied to NIH sponsored human gene mapping projects carried out in the laboratories of Moyra Smith, John Wasmuth and Eric Stanbridge. Dr. Smith's laboratory is continuing studies to assign genes to specific human chromosomes and chromosomal regions through analysis of somatic cell hybrids, studies in cell lines with human chromosomal rearrangements and through the use of in-situ hybridization of DNA probes to specific human chromosomes. They have collaborated in a study which lead to the derivation of a pairwise linkage map for 11 genes on human chromosome 4. Through analysis of these gene loci in cell lines with deletions and rearrangements of human chromosome 4, it will be possible to relate physical and genetic chromosome distance on this chromosome. Studies are also in progress to derive a genetic linkage map and physical chromosome map of human chromosome 9. These studies incorporate the use of hamster human hybrid cell lines in which human chromosome 9 is selectively retained and the use of human cell lines with structural abnormalities of human chromosome 9. Detailed cytogenetic analyses of the neoplastic lesions in Tuberous sclerosis are being carried out to define the molecular basis of this disorder. In Dr. Wasmuth's laboratory funded projects are aimed at defining the molecular genetic defects in Cri-du-chat syndrome and in Huntington's chorea. In order to achieve this it is necessary to do high resolution mapping of DNa fragments in the regions of the genome near the disease gene locus. This physical mapping is being accomplished through the use of somatic cell hybrids produced by fusing rodent cells with human cells containing rearrangements or deletions in the 4p (Huntington's chorea) and 5p regions (Cri-du- chat). For accurate high resolution mapping it is essential that high quality high resolution chromosome analysis be carried out on all cell lines used. A major focus of Dr. Stanbridge's research is to generate a rodent human microcell hybrid clone panel in which each clone contains a single human chromosome while within the complete panel all human chromosomes are represented. A further focus of Dr. Stanbridge's funded research is to investigate the capacity of particular single human chromosomes to suppress the cancer phenotype in cultured cells and in a nude mouse model Detailed high resolution chromosome analysis of microcell hybrids and of transformed cells is critical for the success of these project.